The proposed fight between Manny Pacquiao and Floyd Mayweather Jr has been thrown into jeopardy after the American fighter's camp demanded that both fighters be subjected to Olympic-type drug-testing in the weeks leading up to the bout. Mayweather's manager, Leonard Ellerbe, insisted the fight would not happen if Pacquiao did not agree to blood- testing under standards followed by the United States Anti-Doping Agency, saying: "There is no fight without Olympic-style random drug-testing".

Mayweather's camp claims it was told Pacquiao had agreed to have blood taken for testing before the initial media conference and after the fight but would not agree to have blood drawn within 30 days before the bout. But Pacquiao's trainer, Freddie Roach, said he could live with some testing, as long as it wasn't too close to the fight and wasn't overly intrusive.

"I will not let my fighter take a blood test the day before a fight," Roach said. "If they give me a five-day window or something like that I have no problem with it."

Roach said he hoped the issue was not brought up as a way to get Mayweather out of the fight. "He's looking for a back door out," Roach said. "We're eager to fight."

The fight, which promises to be the richest ever, had widely been expected to be formalised this week, with an official announcement 6 January. It was expected to be held at the MGM Grand hotel on 13 March, with the biggest live gate ever.

But neither fighter has signed formal contracts and there have been disputes between their representatives ever since Mayweather's promoter pulled out at the last minute of a trip to Texas, where the Dallas Cowboys owner Jerry Jones was to make a proposal to host the bout.

But Mayweather's promoter, Richard Schaefer, said all other issues have been agreed upon. "The good news is we have agreed on all the other points," Schaefer said. "Depending on what Manny Pacquiao decides to do we either have a fight or we don't have a fight."

Schaefer said he is still hopeful of the fight happening, based on the fact Pacquiao himself has not publicly said he would not accept blood-testing. "I am still hopeful because I really believe this decision didn't come from Manny Pacquiao, it came from somebody else," Schaefer said. "It's up to Manny Pacquiao to prove me right or wrong."

Pacquiao has never failed a post-fight urine test in Nevada, including his last fight when he stopped Miguel Cotto. Mayweather also has passed urine tests in the state after his fights. Fighters, though, are not routinely tested before bouts for performance-enhancing drugs, and there are no blood tests done for those drugs.

Mayweather's father, Floyd Sr, said after the Cotto fight that he suspected Pacquiao was using performance-enhancing drugs to move up and win titles in so many weight classes. Ellerbe did not make that claim, but said that for a fight of such magnitude fans deserve to be confident neither fighter is cheating.

"If it's good enough for LeBron James, Kobe Bryant, Michael Phelps and Lance Armstrong why isn't it good enough for Manny Pacquiao?" Ellerbe asked. "The fans and sports deserve a level playing field."

Travis Tygart, executive director of the USADA, said he had talked to representatives of both fighters about providing testing. Tygart said he welcomed the request as he would for any sport that does not have stringent Olympic-type testing.

"I think every sport that wants to have clean athletes it's a sign of a step forward to have out of competition testing," Tygart said. "It's an essential thing to do if you want to protect the integrity of the sport. Clean athletes want a level playing field."

Tygart noted Olympic athletes are tested often and without notice. He said less than a teaspoon of blood is removed out of an average of 380 teaspoons in the normal human and that it regenerates within an hour of being withdrawn. Blood tests, he said, can find things urine tests cannot, like the use of human growth hormone, synthetic hemoglobin or blood transfusions, all of which "certainly would aid in an endurance-type event".

Ellerbe said he could not imagine why Pacquiao would not agree, especially considering both fighters would likely make more than $25m (£15.7m) for the bout.

"Only Manny Pacquiao can answer that question," Ellerbe said. "The ball is in his court."